1. Field of the Invention
The present invention relates to a personal computer system that allows information input from different types of input devices, such as a pad-type input-device and a pointing-stick-type (hereinafter simply referred to as the “stick-type”) input device, both of which are integrated into a notebook computer, to be processed by using software.
2. Description of the Related Art
As conventional input devices (controllers) for use in notebook computers, pad-type input devices and stick-type input devices are used.
In a pad-type input device, a quadrilateral flat pad is disposed in the vicinity of a keyboard, and a user slides a finger on the pad so as to input information to move a pointer (mouse cursor) displayed on the screen in the X- and Y-axis directions (i.e., in the plane of the screen). By tapping a finger on the pad, Z-axis information can also be input.
In a stick-type input device, a small-diameter stick is disposed in the vicinity of the center of a keyboard, and a user tilts the stick with a finger in a desired direction so as to input information for moving a pointer displayed on the screen in the X- and Y-axis directions.
By using the pad-type input device, both relative coordinate data and absolute coordinate data can be output to a computer. By using the stick-type input device, only relative coordinate data is output to a computer. The relative-coordinate-data input mode is used for moving a cursor on the computer screen, while the absolute-coordinate-data input mode is used for moving the cursor or manually writing characters, graphics, etc.
Generally, as shown in FIG. 4, the relative coordinate data handled for each type of input device is processed by a three-byte format signal. The first-byte field indicates the overflow bit (YO, XO), the sign bit (YS, XS), button information, etc. The second- and third-byte fields represent X-coordinate and Y-coordinate variable information formed of the X count and the Y count, respectively.
The absolute coordinate data is processed, as illustrated in FIG. 5, by a six-byte format signal. The first-byte field designates ID information for distinguishing the corresponding input device from an external input device (for example, a mouse). The second-, third-, fourth-, fifth-, and sixth-byte fields respectively indicate the X count, the X count and button information, the Y count and button information, the Y count, and the Z count.
However, in the above-described conventional personal computer system, the two types of input devices, such as the pad-type input device and the stick-type input device, cannot be easily used in combination, which causes the following problems.
To input absolute coordinate data by using the pad-type input device (for example, to write characters, such as signatures), a user slides a finger or a pen on the pad. In this case, once the user lifts the finger or the pen away from the pad at the intersection of lines forming a character, the user may not be able to recognize the position from which the user should begin writing the next stroke. This may disturb the balance of the character or make the character illegible, and the user may thus be required to input the character again.
As stated above, conventional pad-type input devices have been employed for inputting characters. However, the resulting operation-data format signals differ between relative coordinate data and absolute coordinate data. Accordingly, a switching operation between the relative-coordinate-data input mode and the absolute-coordinate-data input mode is required. For example, when the user loses track of the input position while operating in the absolute-coordinate-data input mode, the user switches to the relative-coordinate-data input mode. In this case, specific software is required for switching between the relative coordinate data and the absolute coordinate data, and in some cases, the computer must be restarted, thereby reducing ease of operation.